Method of making a bicycle rim

ABSTRACT

A method of manufacturing a rim for a bicycle wheel includes wrapping plys of fibers in a resin matrix around a mandrel; curing the plys to form the rim; and reducing a size of the mandrel to allow the mandrel to be removed from the rim.

RELATED APPLICATIONS

The present application is a continuation, and claims the priority under35 U.S.C. §120, of previous U.S. patent application Ser. No. 10/343,535,filed Oct. 17, 2003, which claims the priority of previous internationalapplication PCT/US00/42246, filed Nov. 20, 2000, which claimed thepriority of U.S. patent application Ser. No. 09/668,867, filed Sep. 25,2000, now U.S. Pat. No. 6,347,839. Applicant claims the priority of alland each of these previous applications, which are hereby incorporatedby reference in their respective entireties.

BACKGROUND

Traditionally, wheel rims have been constructed utilizing very oldstamping processes from metal, typically steel or aluminum, and whilesuch rims are in common use, they possess several undesirablecharacteristics. Steel metal wheel rims corrode, and aluminum wheel rimsare prone to dent and deform, and both types of rims generally offeronly silver color as a finish option. Further, such stamping processeson aluminum require rolling, bending, stamping, and piercing metal thatoften creates micro-fractures and weakened areas of the metal that, inturn, must be heavily reinforced to create sufficient strength to endureover a predictable rim life-span. For a steel rim, while the stampingprocesses create little damage to the metal, such stamping processes arevery capital intensive, requiring heavy forming equipment withsignificant maintenance requirements. In practice, the industryrecognized that a steel rim, with its excessive weight, unattractiveappearance and tendency to corrosion, is not a popular item withconsumers. For example, in North America and Western Europe,manufactures of steel rims are forced to operate at very low profitmargins.

Presently, wheel rims constructed from a glass, carbon and graphitefibers that are attractive to consumers have generally beenprohibitively expense for an average bicycle enthusiast. An example of ahigh quality composite rim whose construction is labor intensive andthus must be sold at a high price is shown in a U.S. Patent Applicationentitled “A Two Component Composite Bicycle Rim”, Ser. No. 09/548,068,filed Apr. 12, 2000, by one of the present inventors.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various examples of the principlesdescribed herein and are a part of the specification. The illustratedexamples are merely examples and do not limit the scope of the claims.

FIG. 1 is an elevation perspective view from the front and side of abicycle having wheels that include the rims of the invention;

FIG. 2 is an enlarged end sectional view taken along the line 2-2 ofFIG. 1, showing a section of the rim of the invention wherefrom thespoke ends have been removed, and showing, in broken lines, a section ofa solid spin cast urethane tire fitted to the rim;

FIG. 3A shows a group of four plys of resin impregnate fiber mats thatoverlay one another at crossing angles of a first or bottom layer offibers at angle B to vertical axis A, followed by a second layer whosefibers are at angle C to vertical axis A, followed by a third layerwhose fibers are at angle D to vertical axis A, with a fourth, or toplayer, having fibers are at angle E to vertical axis A;

FIG. 3B shows the identicals groups of layers of FIG. 3A laid up, oneover the other;

FIG. 4 shows the preferred twenty four (24) plys laid up in repeatinggroups of four (4) plys each aligned for placement against a mandrelforming a laminate having the shape of the rim open area between the rimside walls, with the top group to be laid up first, followed be the nextgroup down, and so on, with the side edges of each group of plys to bebent over the mandrel edges, forming a hook bead type rim hook ends, andshowing the laminate coated mandrel aligned for fitting in the cavity ofa mold to receive a mold cap thereover;

FIG. 5 shows an enlarged end sectional view of the groups of plys laidup on the mandrel of FIG. 4, and fitted into the mold that includes thecap, and showing the mandrel as having a removable center section; and

FIG. 6 shows the mandrel, groups of fiber plys and mold of FIG. 5exploded apart, and shows the center of the mandrel as having beenremoved, allowing half sections of the mandrel to be tilted towards oneanother and pass between the rim side wall hook ends.

Throughout the drawings, identical reference numbers designate similar,but not necessarily identical, elements.

DETAILED DESCRIPTION

The present disclosure provides a composite rim that is formed as a moreuniversal and less expensive bicycle rim, from inexpensive materials,for example carbon plys or glass fibers, and utilizes apparatus andmethod for its manufacture that are more efficient and labor saving. Arim made according to the principles disclosed herein is therefore asstrong as a steel rim and is as light in weight as a comparable aluminumrim, can be attractively finished, and is less expensive and accordinglyhas a broader sales appeal in the market place that steel or aluminumrims. Heretofore, within the knowledge of the inventors, a composite rimlike that of the invention for mounting tires formed with continuousside wall mounting grooves has not been known.

The present specification relates to composite bicycle wheel rims andother like wheel rims where multiple resin impregnated layers or “plys”of fibers are applied at selected crossing angles onto a mandrel to forma laminate, with heat and pressure applied thereto in a molding processto cure the laminate into a composite hook bead type rim that hasinwardly pointing hook ends for fitting into locking grooves formedaround a tire side walls.

A composite bicycle rim, or like rim has heretofore usually beenconstructed in sections from layers or plys of unidirectional fiberlayers that are laid up, one layer over another, on a mandrel, forming alaminate that is then cured under heat and pressure, with the rimsections then finished, assembled and secured together along sectionjunctions, forming a continuous rim. The present disclosure provides, ina single operation, forming a continuous unwarped composite hook beadtype rim having side walls whose upper ends are formed as inwardlypointing hooks that are for fitting into side wall grooves of a moldedtire, for mounting the tire onto the rim. The rim is preferably alaminate constructed by laying up, one over the other, mats or plys ofresin coated or impregnated fiber glass onto a circular mandrel whosewidth can be reduced to pass between the rim side hook ends. Themandrel, as shown, includes movable or removable center sections that,when removed, shorten the distance across the mandrel so as to allow it,after laminate rim curing, to be conveniently removed from between therim side wall hook ends. The hook ends are then shaped, as with aturning router blade, or the like, to extend inwardly a requireddistance from the rim inner side wall ends to hook into the tire sidewall grooves.

To form the rim of the invention, mats or plys of resin epoxyimpregnated or coated directional glass fibers are sequentially laid up,one over the another, forming a laminate, with the fiber direction ofeach mat or ply laid over a prior mat or ply such that the fibers are ata different crossing angles, providing a stack of fiber glass mats orplys where the crossing angles of the fibers of each mat or ply are at aselected angle to adjacent mats. So arranged, a laminate is formedhaving an architecture that is balanced and interlocking, providing afinished rim that is free from residual stress, without stress risersand is dimensionally stable and unwarped.

In one example, a stack of mats containing twenty four (24) discreteresin impregnated mats or plys of fiber glass, each of a thickness offrom twenty eight (28) to thirty four (4) thousands (1000) of an inch,are laid up as a laminate on a mandrel for curing to form the rim. Thetwenty (24) plys are grouped in six (6) identical groups of four (4)plys each that are arranged to cross at the design crossing angles, andrepeat in each of the six (6) identical groups. The first ply in a groupis preferably parallel to the mold circumference, and the last ply inthe group, is preferably, perpendicular to a tangent to the moldcircumference, with the fibers of the center two (2) plys at crossingangles of less than ninety (90) and greater than forty five (45) degreesto one another. So arranged, after curing the laminate is removed off ofthe mandrel by a reduction of the mandrel cross section to allow themandrel or mandrel sections to be slid past the inwardly pointing rimhook ends. So arranged, the rim shape will remain undeformed andfaithful to the cavity of the mold.

After curing and removal from the mold, the rim hook ends as have beenformed by bending the edges of the plys over the mandrel edges, arefinished, as with a router. This finishing provides a required hook enddistance from the rim interior side wall surfaces, and a desired spacingdistance between the hook ends to allow a tire side walls to be fittedinto the rim to with the hook ends passing into the tire side wallcontinuous grooves, mounting the tire mounting onto the rim. Prior towhich tire mounting, the rim is drilled to receive spokes that radiateinwardly therefrom to fit to a hub, forming a wheel. The rim, with thedrilled spoke holes, preferably receives a urethane polymer coatingapplied thereover that enhances the overall rim strength and finishquality, creating a smooth, colorful appearance that is unaffected byultra-violet rays, moisture, salt-water, most chemicals, and mostcleaners.

The present disclosure provides a continuous composite rim that ispreferably formed as a laminate from inexpensive glass fiber mats orplys coated with an epoxy resin that are laid up in groups of mats orplys, with crossing angles between the plys selected to provide, abalanced laminate where the laminate, after curing, is free of stressrisers and is dimensionally stable.

The present disclosure also provides a composite rim that isconveniently and economically formed by laying up epoxy risenimpregnated fiber mats or plys over a mandrel where upper ends of rimwalls are formed as inwardly pointing hook ends by bending mat or plyalong the mandrel parallel edges with, after curing in a mold, themandrel wall to collapse, shortening its width, so as to allow themandrel to pass between the hook ends that are each then machined to adesired distance from the surfaces of the rim interior walls toaccommodate and mount to mounting grooves in a tire side walls.

The present disclosure also provides a composite rim that is easy andeconomical to manufacture to provide a rim that is of like weight to acomparable aluminum rim and is as strong as a steel rim at lower weightthan such comparable steel rim, and can be painted or otherwise coloredto present an attractive appearance.

The present disclosure also provides a composite rim that, afterfabrication, can be easily drilled to accommodate radially mountedspokes thereto that connect to a hub, forming a bicycle wheel.

The present disclosure also provides a rim that receives a urethanepolymer coating after curing to enhance overall rim strength and finishquality, creating a smooth, colorful appearance that is unaffected byultra-violet rays, moisture, salt-water and most chemicals and cleaners.

The invention, as is hereinafter described, relates to a compositebicycle rims, and other vehicle rims, that are formed as a full rims.The composite rim of the invention is formed by laying-up successivelayers of fiber mat or plys, as a laminate, that are, for example, fiberglass mats or plys, but may be carbon, graphite, boron, or otherappropriate fiber mats or plys, within the scope of this disclosure. Themats or plys are coated or impregnated with an epoxy thermoset resin, ora nylon thermo plastic resin, or the like, and fitted onto a mandrel.The mats or plys are preferably laid up on the mandrel in groups of fourplys each, and the mandrel whereon they are laid up is then fitted intoa mold cavity that is closed with heat and pressure are applied to thelaminate, curing the laminate that emerges as a full rim.

As shown in FIG. 1, a rim formed by the principles disclosed herein isfitted with spokes and a hub as a wheel 11 mounting a bicycle tire 12.Though, of course, a rim for another appropriate vehicle could be formedlike that of the rim 10, within the scope of this disclosure. In FIG. 2,the rim 10 is shown as an enlarged section and includes a section oftire 12 fitted thereto, as shown in broken lines. The rim 10, as shownin FIGS. 2, 3B, 4, 5 and 6, is preferably formed from groups 14 of four(4) plys 13 a, 13 b, 13 c and 13 d, for each group 14 that are laid upupon a mandrel 15. The groups 14, as shown best in FIG. 4, arepositioned over one another, for curing in a mold 16, as shown in FIGS.4, 5 and 6. Shown in FIG. 3A, the individual plys 13 a, 13 b, 13 c and13 d, of the four (4) plys that make up each group 14 are formed fromfibrous mats or plys, preferably fiber glass mats or plys, forming a rim10 that is as light as a comparable aluminum rim, but is less expensivethan an aluminum rim, and which rim 10, when cured, is as strong as acomparable steel rim. Through, it should be understood, mats or plys ofother fibers such as carbon, graphite, boron, or the like, could be soused within the scope of this disclosure.

The fibers of each ply are directional and are laid up in groups 14 onmandrel 15, as shown in FIG. 4. The groups 14, as set out above, areidentical to one another and are formed, as shown in FIG. 3A, by layingup the four (4) plys that make up a group 14 onto mandrel 15. Startingfrom the bottom ply of FIG. 3A, ply 13 a has its fibers are at zerodegrees to Axis A and parallel to the mandrel circumference, and isfirst positioned on mandrel 15, followed by plys 13 b, 13 c, with ply 13d then positioned thereover with its fibers perpendicular to axis A andperpendicular to a tangent to the mandrel circumference.

To provide a strong, stable and balanced laminate that does not haveresidual stresses and so is dimensionally stable upon removal from themold 16. The plys 13 a, 13 b, 13 c and 13 d are arranged at selectedcrossing angles. Such a balanced laminate, in practice, is not easilyachieved, with proper fiber direction and selected laminate thicknessrequired to achieve this optimal condition. If such balanced laminate isnot achieved the casting will include stress risers and be dimensionallydeformed.

In one example, for a rim 10, that is shown as a broad rim and isappropriate for use as part of a mountain bike wheel, the requiredlaminate architecture requires that the fibers of the ply 13 a be laiddown at a zero angle to a vertical axis A, parallel to the circumferenceof the mold 16, with a next ply 13 b laid thereon at, preferably, a plusthirty eight (38) degrees to the vertical axis A, followed by a next ply13 c laid thereover that, preferably, is at a minus thirty eight (38)degrees to the vertical axis A, with, finally, the ply 13 d laidthereover, is, preferably, at ninety (90) degrees to vertical axis A,and is perpendicular to a tangent to the mold circumference, forming agroup having a thickness of from between twenty eight (28) and thirtyfour (34) thousands (1000) of an inch. Accordingly, in practice, ply 13a is placed against the mandrel 15 surface, ply 13 b is positioned overply 13 a, followed a placement of ply 13 c over the ply 13 b, and,finally, ply 13 d is placed over ply 13 c. So arranged, the bottom andtop plys, 13 a and 13 d, respectively, are, respectively, aligned with,and are perpendicular to, the mold circumference, with the inner plys 13b and 13 c, respectively, at design crossing angles to one another. Forthe single group 14, the plys crossing angles are therefore from zero(0) degrees to ninety (90) degrees, with the groups each crossing oneanother at their contact plys at ninety (90) degrees or at right angles.In practice, the center plys 13 b and 13 c crossing angles, as arepreferred, are at, respectively, plus thirty eight (38) and minus (38)degrees, to axis A. Which crossing angles, however, can, in practice, beplus or minus five (5) degrees to the preferred plus thirty eight (38)and minus thirty eight (38) degrees and still maintain a desired plybonding, as a balanced laminate. The balanced laminate will retain themold cavity shape, without stress risers and dimensional deformation orwarping or going out of round, after removal from mold 16, as set outbelow.

In laying up the groups 14 of plys 13 a, 13 b, 13 c and 13 d, and withthe groups 14 stacked upon one another, the order of stacking is thatthe top ply 13 d in a group 14 is in contact with the bottom ply 13 a ofthe group stacked thereon, and with the individual plys 13 a and 13 d ofeach group are in contact with ply 13 a and 13 d of the adjacent stackedgroups. So arranged, the ply fibers at the junctions of which groups areat ninety (90) degrees to one another. To form the rim 10, as a balancedlaminate, preferably six (6) groups 14 are laid up upon one another onmandrel 15, though, it should be understood other numbers of plys inmultiples of fours can constitute a group, such as eight (8), andtherefore other number of groups than six (6) can be laid up as thelaminate, within the scope of this disclosure. Accordingly, it should beunderstood that, for another rim configuration such as a differentbicycle rim than a mountain bike rim, or for a scooter rim, or for aneven a larger vehicle rim, the number of groups 14 and plys within thegroup, can be varied for the type of vehicle the rim 10 is being formedfor.

The mandrel 15, as shown in FIGS. 4, 5 and 6, is shaped around the sides15 a and across the bottom 15 b thereof, to essentially have, theprofile of the bottom area 12 a of tire 12, that is shown in brokenlines in FIG. 2. Shown in FIG. 2, the mandrel is split longitudinally at17, dividing the mandrel into mirror image half sections 18 and 19 thatinclude slot sections 18 a and 19 a, respectively, formed in theabutting surfaces, along split 17. Which slot sections 18 a and 19 a areeach shown as stepped above the mandrel bottom 15 b to form a slot thatis to receive a bar 20 fitted therein. In practice, the mandrel halfsections 18 and 19 are preferably formed as arcuate sections that arefitted together, each to form a continuous ring, and the half sectionsare, in turn, fitted together to form the mandrel 15. With the mandrelsections 18 and 19 held together as by fastener means, not shown, toform the continuous ring shaped mandrel 15. Which mandrel receives theply groups 14 laid thereover, extending around the mandrel, and with thegroups 14 sides bent over the mandrel top edges, forming the rim hookends 31 a and 31 b, as shown in FIGS. 2, 5 and 6. After curing, as setout below, the bar 20 sections are removed, as shown in FIG. 6, allowingthe mandrel arcuate sections 18 and 19 to collapse towards one anotherand allow them to individually be removed from the rim 10, passingbetween the rim hook ends 31 a and 31 b, as shown in FIG. 6, and asdiscussed hereinbelow.

To lay up the groups 14 of plys 13 a, 13 b, 13 c and 13 d, the groups,as shown in FIG. 3A, are cut to be long enough to fit around the mandrel15 inner circumference, covering the mandrel bottom 15 b and extendingover the mandrel sides 15 a, to lap over the mandrel sides 15 a topedges, or the groups 14 edges are fitted into grooves 18 b and 19 b,respectively, that are formed along which top edges, as shown in FIG. 5.The over lapped portions of groups 14 of plys as are laid up over themandrel top edges or as are fitted into grooves 18 b and 19 b, form theinwardly pointing hook ends 31 a and 31 b of the rim 10 side walls ofthe finished rim.

With the groups 14 laid up over mandrel 15 that is formed in sectionsthat are joined into a continuous ring and the assembly is fitted intomold 16 that includes a mold base 21. The mold base 21 has a cavity 22formed therein that duplicates the rim 10 outer surface. A cap 23 isincluded that is joined in sections to be continuous for fitting overthe mold open end and has a center groove 24 and side grooves 25 a and25 b that individually receive and press against, respectively, thecenter bar 20 and in-turned top sections of the groups 14 of plys ashave been fitted into the mandrel grooves 18 b and 19 b. So arranged,the mandrel 15 applies pressured onto the inner surface of the laid upgroups 14, in the mold cavity 22, compacting the laid up groups 14between the mold and mandrel surfaces. Heat is added through mold 16such that the groups 14 of plys that have been coated or impregnatedwith an epoxy resin are cured, with the resin flowing through andbinding the fibers together, forming the composite rim 10. Whereafter,the rim 10 containing the mandrel 15 is removed, as shown in FIG. 6, andthe center bar 20 sections are pulled out from the mandrel sections 18and 19 groove segments 18 a and 19 a. The mandrel sections 18 and 19 arethereby freed to individually pass out from between the rim 10 sidewalls 30 a and 30 b hook ends 31 a and 31 b.

The composite rim 10 can then be smoothed as by sanding, sand blasting,or other process or procedure for smoothing a surface and, as needed,the ends of hook ends 31 a and 31 b can be finished, as by passing arouter therebetween to provide a desired spacing distance so that thehook ends snugly fit into mounting grooves 12 b of tire 12, as shown inbroken lines in FIG. 2, locking the tire 12 onto the rim 10.

The rim 10 can be drilled, forming holes 33 through a rim bottom web 32that are to receive spoke ends fitted through and secured to the rimweb. The spokes are connected, on their opposite ends, to a hub, and therim 10, spokes and hub form the wheel 11, as shown in FIG. 1. The rim 10laminate surface is then finished by an application of a urethanepolymer coating 35, as shown in FIG. 2, that can itself be colored, caninclude colored chips, mica chips, or the like, and can serve as a basecoat to be painted, or the like. The polymer coating 35 provides anenhancement to the overall rim strength, and, in addition, provides afinish to the glass fiber surface that creates a smooth, colorfulappearance that in unaffected by ultra-violet rays, moisture, saltwater, most chemicals, and most cleaners. The urethane polymer enhancesrim strength and may be applied to both the rim 10 outer and innersurfaces, with the smooth finish on the rim inner surface to facilitatefitting tire 12 therein.

It should be understood that the invention in rim 10 is not limited toany particular arrangement of mandrel 15, so long as that arrangementallows the mandrel to be removed and pass between the inwardly facingrim side wall hook ends 31 a and 31 b. Accordingly, a mandrel to receivethe individual groups 14 of individual plys 13 a, 13 b, 13 c and 13 d,can be any mandrel arrangement where the mandrel cross section can bereduced to allow the mandrel to pass out from within the finished rim10, passing between the rim hook ends. For example, the mandrel, ratherthan being formed by expanding sections, can be a tubular shaped bladderthat, when inflated with air, provides a surface to receive the groups14 of fiber glass plys laid up thereover, and that, when deflated, willcollapse sufficiently to be pulled out from between the rim side wallhook ends 31 a and 31 b. Such bladder may or may not including slots 18b and 19 b formed around the side top edges, that the plys are fittedinto to form the hook ends. With, if slots 18 b and 19 b are notprovided, the hook ends 31 a and 31 b can then be formed by bending theedges of the groups of plys over the mandrel edges. For eitherprocedure, the formed hook ends 31 a and 31 b need to be finished aftermandrel removal, as with a router, or like tool, to where each hook endextends a desired distance inwardly from the rim side wall inner surfaceand is smooth so as to fit into the tire mounting rim groove.

Hereinabove has been set out a description of a preferred composite rimof the invention shown herein as a bicycle rim though, it should beunderstood the invention can be applied to rims additional to bicyclerims. Accordingly, it should be understood that the present inventioncan be varied within the scope of this disclosure without departing fromthe subject matter coming within the scope of the following claims, anda reasonable equivalency thereof, which claims we regard as ourinvention.

The preceding description has been presented only to illustrate anddescribe embodiments and examples of the principles described. Thisdescription is not intended to be exhaustive or to limit theseprinciples to any precise form disclosed. Many modifications andvariations are possible in light of the above teaching.

What is claimed is:
 1. A method of manufacturing a rim for a bicyclewheel, said method comprising: wrapping plys of fibers in a resin matrixaround a mandrel; curing the plys to form the rim; reducing a size ofthe mandrel to allow the mandrel to be removed from the rim; andremoving the mandrel from the rim.
 2. The method of claim 1, whereinreducing a size of the mandrel comprises deflating an inflatable portionof the mandrel.
 3. The method of claim 1, wherein reducing a size of themandrel comprises disassembling the mandrel into two or more constituentmembers.
 4. The method of claim 3, wherein disassembling the mandrelcomprises removing a center section that, when removed, shortens adistance across the mandrel so as to allow the mandrel, after saidcuring, to be removed from the rim.
 5. The method of claim 1, furthercomprising shaping inwardly extending hooks from edges of the cured plysof the rim, said hooks extending around the rim that will hook into sidewall grooves of a bicycle tire.
 6. The method of claim 5, wherein saidhooks are shaped with a turning router blade.
 7. The method of claim 1,wherein said fibers are made of carbon.
 8. The method of claim 1,wherein the fibers of a particular ply are arranged in a commondirection and wrapping said plys further comprises disposing a sequenceof plys on said mandrel such that the fibers in successive plys arearranged at different crossing angles.
 9. The method of claim 1, furthercomprising drilling holes to receive spokes around a circumference ofsaid rim.
 10. The method of claim 1, further comprising coating aurethane polymer over the rim after curing.
 11. A method ofmanufacturing a rim for a bicycle wheel, said method comprising:wrapping plys of fibers in a resin matrix around a mandrel, the mandrelcomprising multiple pieces; curing the plys to form the rim;disassembling the multiple pieces of the mandrel to allow the multiplepieces of the mandrel to be removed from the rim.
 12. The method ofclaim 11, wherein the multiple pieces of the mandrel comprise aremovable center section that, when removed, shortens a distance acrossthe mandrel so as to allow the mandrel, after curing, to be removed fromthe rim.
 13. The method of claim 11, further comprising shaping inwardlyextending hooks from edges of the cured plys of the rim, said hooksextending around the rim that will hook into side wall grooves of abicycle tire.
 14. The method of claim 13, wherein said hooks are shapedwith a turning router blade.
 15. The method of claim 11, wherein saidfibers are made of carbon.
 16. The method of claim 11, wherein thefibers of a particular ply are arranged in a common direction andwrapping said plys further comprises disposing a sequence of plys onsaid mandrel such that the fibers in successive plys are arranged atdifferent crossing angles.
 17. The method of claim 16, wherein fibers ina first ply on the mandrel are parallel to a circumference of themandrel and fibers in a last ply on the mandrel are perpendicular to atangent to the mandrel circumference.
 18. The method of claim 16,wherein said crossing angles are less than 90 degrees and greater than45 degrees.
 19. The method of claim 11, further comprising drillingholes to receive spokes around a circumference of said rim.
 20. Themethod of claim 11, further comprising coating a urethane polymer overthe rim after curing.